Chemiluminescent smokes

ABSTRACT

CHEMILUMINESCENT SMOKE, THAT IS, A SMOKE VISIBLE BOTH BY DAY AND NIGHT, IS PRODUCED WHEN A COMPOSITION CONSISTING ESSENTIALLY OF (A) AN ALUMINUM ALKYL, (B) AN ETHER OR AN AMINE COMPLEXING AGENT, AND (C) AN ACRIDINE, IS CONTACTED WITH AIR AND WATER.

United States Patent O 3,576,754 CHEMILUMINESCENT SMOKES Urho AlbertLehikoinen, Detroit, Mich., assignor to Ethyl Corporation, New York, NY.No Drawing. Filed June 29, 1967, Ser. No. 649,838 Int. Cl. C09k 3/00 US.Cl. 252188.3 16 Claims ABSTRACT OF THE DISCLOSURE Chemiluminescentsmoke, that is, a smoke visible both by day and night, is produced whena composition consisting essentially of (a) an aluminum alkyl, an etheror an amine complexing agent, and (c) an acridme, is contacted with airand water.

BACKGROUND OF THE INVENTION which would appear as a smoke during daytimeand as a chemiluminescent cloud at night.

SUMMARY OF THE INVENTION An improved smoke-producing material isprovided by a composition consisting essentially of (a) a trialkylaluminum or an aluminum or an aluminum alkyl hydride which is previouslycomplexed with (b) a complexing agent selected from a monoether, di-

ether, or a triether or a tertiary amine, and admixed with (c) anacridine.

When the above composition comes in contact with air and water, a cloudof smoke visible both by day and night is formed.

PREFERRED EMBODIMENTS This invention pertains to chemiluminescent smokescontaining an alkyl aluminum and an acridine.

The particular feature of the smoke produced by a composition of thisinvention is the luminescent property; that is, visibility both by dayand night.

An object of this invention, which is to prepare a nightvisibile smoke,is satisfied by providing compositions consisting essentially of (a) analuminum alkyl having the formula RR'R"Al or an alkylaluminum hydridehaving the formula RR'AlH or mixtures of said hydrides and/or aluminumalkyls wherein R, R and R are alkyl radicals of l to 4 carbon atoms,said aluminum compound being complexed with a chemically equivalentamount of (b) a complexing agent selected from (1) an ether having up toabout carbon atoms and 1 to 3 ether-oxygen linkages, said ether beingfree of acetylenic bonds, and (2) a tertiary amine having up to about 24carbon atoms, the complexed aluminum alkyl being admixed with (c) fromto weight percent of an acridine.

These compositions yield chemiluminescent smoke clouds when they come incontact with air or any other oxidizing agent and water. The method ofwater mixing is not critical. The smoke agent may be injected underneaththe surface of water to yield a cloud of chemiluminescent smoke abovethe surface of the water. Alternatively, the smoke agent can be merelyadmixed with water by shaking the agent and water in a vessel. Anothermethod for contacting the agent with water is to introduce a stream ofthe agent into a water spray.

Although a larger and more intense smoke cloud is produced when thecomposition of this invention is reacted with large quantities of water,satisfactory results are also obtained when the only water present isthe water vapor normally present in the air or the water of hydrationpresent in a compound such as an alum, when such a compound is admixedwith the smoke-producing composition.

One essential ingredient in the smoke compositions of this invention isan aluminum compound of the types given above. Preferably, all alkylradicals bonded to the aluminum atom are identical. Most preferably,these alkyl radicals are solely composed of carbon and hydrogen and haveup to four carbon atoms. Typical examples of alkyl aluminums which areapplicable in this invention are trimethylaluminum, triethylaluminum,diethylaluminum hydried, methyldiethylaluminum, triisopropylaluminum,trisec-butylaluminum, and the like.

For the purposes of this invention, the aluminum alkyl is complexed witheither an ether or an amine. A wide variety of ethers can be employed.The exact nature of the ether is not critical provided it can complexwith the aluminum compound and is devoid of substituent groups whichlead to deleterious side effects. Preferably, the ethers have less thanabout 15 carbon atoms. They may have one, two, or three or more etherlinkages, O. More preferably, the ethers employed in this invention arefree from acetylenic linkages.

Monoethers which may be employed have the formula wherein R and R areindependently selected from alkyl groups having 1 to 4 carbon atoms;aryl groups such as phenyl and tolyl; alkenyl groups of 3 to 5 carbonatoms such as allyl; cycloalkyl groups such as cyclohexyl, and the like.Typically preferred ethers of this type are diethyl ether, isopropylether, allyl ether, phenyl ether, 'benzyl ether, benzyl ethyl ether,a-methylbenzyl ether, and the like. Cyclic monoethers can be employed. Ahighly preferred ether which ,in used in this invention istetrahydrofuran. Biethers, that is, ethers which contain two etheroxygen linkages, can be employed in this invention. Typical ethers ofthis type which may be employed are ethylene glycol diethyl ether,ethylene glycol dibutyl ether, ethylene glycol diamyl ether, and thelike.

Triethers (sometimes referred to as tridentate ethers) which may beemployed in this invention preferably have the ether oxygen linkagesseparated by two carbon atoms; that is, ethylene radicals. Typicalethers of this type which can be employed in this invention arediethyleneglycol dimethylether, diethyleneglycol diethylether, anddiethyleneglycol dibutylether.

As mentioned above, aluminum alkyls can also be complexed with an amine.A wide variety of tertiary and hindered secondary amines can beemployed. The exact nature of the amine is not critical, provided it cancomplex with the aluminum compound and is devoid of substituent groupswhich lead to deleterious side effects. Any tertiary amine may beemployed, but for practical reasons, tertiary amines having up to about15 carbon atoms are preferred. Illustrative examples of applicableamines are N,N-dimethylaniline, dicyclohexylamine, N-benzyl-N-ethylaniline, N benzyl N ethyl m toluidine, di-

benzylamine, ditolylamine, diisobutylamine, tert-butylamine, N,Ndiethylaniline, tribenzylamine, tri noctylamine, triphenylamine, N,Ndimethylbenzylamine, dodecyldimethylamine, N,N di methyl-o, m, andptoluidines, N,N diethyl-o-m, and p-toluidines, N,N- ethylmethylanilineand the like. Preferably, the amines are selected fromhexamethylenetetramine and tetra (lower alkylene) diamines andhexa(lower alkylene) diamines such as tetramethylenediamine,tetraethylenediamine, tetrapropylenediamine, tetrabutylenediamine,hexamethylenediamine, hexaethylenediarnine, hexapropylenediamine,hexabutenediamine, and the like.

Although the above-described complexing agents are preferred, othercomplexing agents may also be employed. Examples of such additionalagents are thioethers, organic phosphines such as tributylphosphine,trioctylphosphine, and triphenylphosphine, and metal salts, especiallyalkali and alkaline earth metal salts such as lithium chloride andtriethylaluminum-sodium fluoride complex.

The complexing of the alkyl aluminum with an ether or an amine abovedescribed is readily carried out by simply mixing the complexing agentand the alkyl aluminum under anhydrous conditions and in the presence ofan inert atmosphere. Typically, nitrogen is used to provide the inertatmosphere. However, other inert gases such as argon and neon can beemployed, if desired, Best results are obtained when all of the alkylaluminum is complexed. When using a monoether, at least one mole ofether is employed for each mole of alkyl aluminum. Similarly, when adiether is employed, at least one-half mole of ether is employed foreach mole of alkyl aluminum. Furthermore, with tridentate ethers themole ratio of ether to aluminum is at least 1 to 3. When using adiamine, at least one-half mole of amine is employed for each mole ofalkyl aluminum. Similarly, when a tetramine is employed, at leastone-quarter mole of amine is employed for each mole of alkyl aluminum.

It is not necessary to employ an exactly chemiequivalent amount of acomplexing agent and alkyl aluminum. An excess of ether or amine can beused. When volatile complexing agents such as diethyl ether areemployed, an excess of the complexing agent may be beneficial. In someinstances, it appears that the presence of an excess of a complexingagent yields a larger smoke cloud. Consequently, it is convenient toemploy up to 5 equivalents of a complexing agent for each equivalent ofalkyl aluminum.

Another important ingredient in the compositions of this invention isacridine and its derivatives having the following structure:

Illustrative examples of acridines and their derivatives useful in thisinvention are acridine, benz[c]acridine, 4- methylacridine,3,5-dipropylacridine, 4-ethyl-6-hexylacridine,1,4,6,S-tetraethylacridine, and the like.

After the alkyl aluminum is complexed, it is then mixed with an amountof an acridine which is sufficient to yield a final preparationcontaining from to 50 weight percent of an acridine of the typedescribed above. The mixing of the complex with a acridine compound isconveniently carried out using simple mixing procedures. As in the caseof complexing, a slight amount of heat may be beneficial; that is, itmay be desirable to heat up the mixture to a temperature within therange of -50 C.

As pointed out above, the chemiluminescent smoke formulations of thisinvention yield smoke clouds which are visible at night when contactedwith air and water. The water need not be pure; natural waters such aslake, river or sea water can be employed as can muddy or wet earth. Inaddition, the water may be chemically bound;

that is, waters of hydration. When using chemicallybound water, acompound which preferentially contains a large amount of waters ofhydration is employed. Preferred compounds containing waters ofhydration are alums. Typical alums which may be used are described onpp. 196-199 of the 8th edition of Langes Handbook of Chemistry, HandbookPublishers, Inc., S'andusky, Ohio (1952).

To further illustrate the invention, the following nonlimiting examplesare presented. Unless otherwise indicated, all parts are by weight.

EXAMPLE 1 Two hundred and twenty-six milliliters of diethyl ether isadmixed with 290 mls. of triethylaluminum under anhydrous conditions andin the presence of a nitrogen atmosphere. This yields a diethylether-triethylaluminum complex. T o the resultant mixture is added 250grams of acridine.

The resultant smoke formulation yields a chemiluminescent smoke whenadmixed with water in air. For example, equal volumes of agent and waterwhen admixed together yield a chemiluminescent smoke. Furthermore, sucha smoke is produced when one volume of agent is injected under thesurface of approximately 10 volumes of water without stirring. Thirdly,the formulation yields a chemiluminescent smoke when 50 parts of theformulation are added to parts of [Cr (SO -K SO -24H O].

EXAMPLE 2 Following the procedure of Example 1, smoke formulationscontaining equimolar amounts of diethyl ether and triethylaluminum and40 percent of benz[c]acridine are prepared. When these formulations areadmixed with water, chemiluminescent smokes are produced.

Similar results are obtained when benzacridine is re placed by4-methylacridine, 8-phenylacridine, and 6,9-diisopropylacridine.

EXAMPLE 3 Equimolar complexes of tetrahydrofuran with triethyl aluminumand dioxane with triethylaluminum are prepared using the procedure ofExample 1. They are ad mixed with sufficient quantities of3-hexylacridine to yield formulations containing 20, 30*, 40, and 50weight percent of the acridine.

EXAMPLE 4 Seven parts of hexamethylenetetramine is admixed with 22.8parts of triethylaluminum under anhydrous conditions and in the presenceof a nitrogen atmosphere. This yields an aminetriethylaluminum complex.To the resultant complex is added 0.9 part of tet-rahydrofuran and then20 parts of 5-tolylacridine.

This smoke agent has the following formulation:

Wt. percent Texamethylenetetramine 13.8 Triethylaluminum 45.0S-tolylacridine 39.5 Tetrahydrofuran 1.8

The tetrahydrofuran is not a critical ingredient but aids bitol anisole,p-chloroanisole, veratole, a-methylbenzyl ether, and benzyl ether areprepared.

The smokes of this invention which are visible at night have manyutilities. For example, they can be employed for marking purposes in searescues. Similarly, they may be used to direct artillery fire or aerialbombardments.

An impotant aspect of this invention is that the smokes are visible byday and at night. Hence, they have daytime and nighttime utilities.Accordingly, to compositions of this invention have a dual function. Itis believed that this dual function is not accomplished by smokes andflares presently in use.

Having fully described the novel compositions of this invention, theirmethod of preparation, and their utility, it is desired that the scopeof this invention be solely limited by the lawful extent of the appendedclaims.

What is claimed is:

1. A chemiluminescent smoke composition being prepared by mixing (a) analuminum alkyl having the formula:

wherein R, R and R" are alkyl radicals of 1 to 4 carbon atoms, saidaluminum alkyl being complexed with at least a chemically equivalentamount of (b) a complexing agent selected from the group consisting of(i) an unsubstituted ether having up to about carbon atoms and 1 to 3ether-oxygen linkages, said ether being free of acetylenic bonds, and(ii) a tertiary amine having up to 15 carbon atoms, the complexedaluminum alkyl being admixed with (c) from to 50 weight percent (basedon the weight of the total smoke composition) of an acridine selectedfrom the group consisting of acridine, alkylsubstituted acridine, andaryl-substituted acridine, said alkyl groups having from 1 to 6 carbonatoms and said aryl groups being phenyl or tolyl groups.

2. A smoke composition of claim 1 wherein said aluminum alkyl istriethylaluminum.

3. A smoke composition of claim 2 wherein said acridine is alkylsubstituted, said alkyl substituents having up to about 6 carbon atoms.

4. A smoke composition of claim 2 wherein said acridine is selected fromthe group consisting of acridine, benZIcJacridine, 4-methy1acridine,1,4,6,8-tetraethylacridine, 3,5-dipropylacridine, 3-hexylacridine,2-phenylacridine, and S-tolylacridine.

5. A smoke composition of claim 2 wherein said complexing agent is anunsubstituted monoether having the formula:

R -O-R wherein R and R are independently selected from alkyl groupshaving 1 to 4 carbon atoms, alkenyl groups having 3 to 5 carbon atoms,cyclohexyl, phenyl, and tolyl groups.

6. A smoke composition of claim 5 wherein said acridine is selected fromthe group consisting of acridine, benz[c]acridine, 4-methylacridine,l,4,6,8-tetraethy1acridine, 3,5-dipropylacridine, 3-hexylacridine,8-phenylacri dine, and 5-to1ylacridine.

7. A smoke composition of claim 2 wherein said complexing agent is atertiary amine selected from the group consisting ofhexamethylenetetramine, terta(lower alkylene) diamine, and hexa(loweralkylene)diamine, said lower alkylene groups having from 1 to 4' carbonatoms.

8. A smoke composition of claim 5 wherein said complexing agent isdiethylether.

9. A smoke composition of claim 2 wherein said complexing agent istetrahydrofuran.

10. A smoke composition off claim 2 wherein said complexing agent isdioxane.

11. A smoke composition of claim 7 wherein said complexing agent ishexamethylenetetramine.

12. A smoke compositionof claim 7 wherein said complexing agent isN,N,N,N-tetra(lower alkyl)-ethylenediamine, said lower alkyl grouphaving from 1 to 4 carbon atoms.

13. A smoke composition of claim 11 wherein said acridine is selectedfrom the group consisting of acridine, benz[c]acridine,4-methylacridine, 1,4,6,8-tetraethylacridine, 3,5-dipropylacridine,3-hexylacridine, 8-phenylacridine, and 5-tolylacridine.

14. A smoke composition of claim 8 wherein said acridine is acridine.

15. A method for producing a chemiluminescent smoke, said methodcomprising contacting a smoke composition of claim 1 with air and water.

16. A method of claim 15 wherein said water is from an alum having theformula [Cr (SO.,) -K SO -24H O].

References Cited UNITED STATES PATENTS JOHN D. WELSH, Primary ExaminerUS. Cl. X.R. 252-3012, 305

Po-ww UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.5,576,75H Dated April 27, 1911 Inventnflg) Urho Albert Lehikoinen It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 1, line 36, delete first occurrence of "or an aluminum Column 2,lines 25 and 26, "hxdried" should read hydride line 40, the formula "R-O-R should read R -O-R Column l, line 56, "Texamethylenetetramine"should read Hexamethylenetetramine Column 5, line 7, impotent" shoulread important line 9, "to" should read the 3 lin 19, (Claim "2" shouldread 8 Column 6, line 1 (Claim 7), "terta(lower" should read tetra(lower5 lin 21, (Claim 10), "off" should read of Signed and sealed this 2L .thday of August 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting OfficerCommissioner of Patents

